Liquid fuel injection pump for internalcombustion engines



Feb. 15, 1955 D. G. BURTON LIQUID FUEL INJECTION PUMP FORINTERNAL-COMBUSTION ENGINES Filed Dec. 21, 1953 as'itisnot consistentwithgoodre tssuchthatwhen theenglneieatjo-resttbeeontrelberoeeupiesalimitpolittcnin United States Patent Ofiice'2,102,029 Patented Feb. 15, 1955 LIQUID FUEL INJECTION PUMP FOR INTERNALCOMBUSTION ENGINES DoIglasGBartom-Breatf EnglanflasalperloQLV.Umited,Aet?:'London,EngI-d Applieatiol December 21, 1953, Serial No.399,354

Claims priority, application Great Brltfi Deeeniser 23, 1952 1 Claim-(Cl- 123-14.)

This invention relates to liquid fuel injection pumps for internalcombustion engines, and has for its object to provide in a simple form apump of the reciprocatory plunger type having combined with it agovernor responsive to the air-pressure in the air-intake manifold ofthe engine for actuating a slidable control bar, the pump output beingvariable by relative angular movement of the plunger (or each plunger)and its associated barrel under the action of the said bar.

The invention comprises a pump of the type aforesard of which (1) thegovernor comprises a chamber divided into two compartments by aspring-loaded flexible diaphragm or piston, one of the compartmentsbeing adapted for connection with the air-intake manifold of the engine,and having therein a stabiliser consisting of a spring-loaded movableabutment for steadying the movements of the diaphragm or piston, and ofwhich (2) the spring loaded discharge valve of the pump barrel, or eachbarrel, is of the poppet type, the closure member of which has combinedwith it a cylindrical part which (when the valve is closed) occupies acylindrical bore extending from the valve seatin and which is movedbeyond the seating when the cosure member is fully open, the closuremember or the barrel having therein also a by-passage arranged to permita restricted flow of fuel before the closure member is fully opened.

In the accompanying drawings,

Figure l is a part sectional side elevation of a multiplunger fuelinjection pump combined with a governor in accordance with theinvention.

Figure 2 is a sectional elevation illustrating one of the pgmp plungersand its associated barrel and discharge v ve.

valve.

A pump embodying the invention may so far as the pumping means areconcerned, he of any convenient and conventional construction, and itmay include a single reciprocatory plunger, or a plurality of suchplungers arranged parallel with each other. The output of the pump isvariable in known manner by the provision in the plunger a or eachplunger of a spill passage b which is brought into action by angularmovement of the plunger relatively to discharge ports 0, in the barrel,film movement beingoeitfected by a slldable control bar 41 carried inthe y part of the pump. Alternatively the spill may be controlled byangular movement of the barrel by the bar d.

For actuating the control bar d, one end of it is -'con nected to agovernor responsive to the air pressure in the air-intake manifold e ofthe engine, as shown in Figure 1. According to the invention thegovernor consists of a cylindrical chamber 1 which is divided into twocompartments by a flexible diaphragm g (or piston) loaded by a spring h,and one of the compartments is provided with a connection for a pipe ileading to the said manifold at a position between the manifold throttlevalve 1 and the engine, the other compartment being open to theatmosphere. In the first mentioned compartment is also contained astabiliser. Thts consists of a movable abutment I: loaded by a spring m,which when the diaphragm is moved into contact with it serves tosupplement the action of the spnpg h acting on the drahragtn and henceprevent hunting. Such an increa e in spring resistance is found to berequired at low engine and loads, but is not desirable: tother eondi onsa on.

Thearrangemeut width Figure 3 illustrates an alternative form of thedischarge the pump is able to give its maximum output. Movement of thecontrol bar from this position under the action of the governor servesto reduce the pump output.

The second feature of the invention consists in the combmatron with thedischarge end of the pump barrel in (Figure 2) or each barrel, of adischarge valve of a poppet type of the following form.

The closure member of the valve (which is loaded by a spring 0)comprises a head p having a frustro-coni-' cal part which co-operateswith an annular seating at the outlet end of a cylindrical bush qsituated at the discharge end of the barrel. On the stem r of theclosure member is formed a short cylindrical land which when the valveis closed lies within the said bush. This land must be moved through theseating by a distance 8",

(Figures 2 and 3) before the full discharge can occur. Also in the stemof the closure member is formed an axial bore r leading to a by-passpassage u of small diameter having its discharge end situated beneaththe head of the closure member as shown. The arrangement is such thatduring the discharge stroke, the initial movement of the closure memberallows fuel to pass along the bore 1 and through the passage u at arestricted rate which depends on the speed of the pump. Later and whenthe land has been moved past the seating a full and unrestricted outflowoccurs through the ports v.

In the example shown in Figure 2, the ports v open into an annulargroove w around the stem of the closure member. Alternatively and asshown in Figure 3, the ports v may be made of larger diameter than thoseshown in Figure 2 and arranged to extend to the surface of the stern ofthe closure member.

If desired the equivalent of the passages t and u may be provided in thebush q instead of in the closure memit has been found that when a pumpis provided with a simple governor as above described, the stabilisertends to exert an excessive resistance to movement of the diaphragm athigh pump speeds and thereby interferes with the desired restriction ofthe pump out-put'at such speeds. To obviate this condition variousmodifications of the governor have been devised and used but theseresult in the disadvantage of arelatively complex governor construction.By the combination with the pump of a discharge valve or valves as abovedescribed instead of a valve of conventional construction thisdisadvantage is obviated, and a satisfactory regultaion of the pumpoutput over a wide range of speed and with the throttle in any position,can be obtained with a governor of simple construction.

Having thus described by invention what I claim as new and desire tosecure by Letters Patent is:

Means for supplying liquid fuel to an internal combustion engine,comprising in combination a liquid fuel injection pump having at leastone reeiprocatory plunger and a barrel in which the plunger is movable,a sltdable central bar for effecting relative angular movement of theplunger and barrel to vary the pump output, a governor having a chamberdivided into two compartments by a spring loaded member which isresponsive to arr pressure for actuating the control bar, one of thecom- .partments being adapted for connection to the air-intake manifoldof the engine, a stabiliser consisting of a spring loaded abutmentarranged in the chamber to co-operate with the said spring loaded memberfor steadying the movements thereof. and a spring loaded discharge valveof the poppet type for controlling the delivery of fuel from the barrelby the plunger, the discharge valve comrising a closure member having acylindrical land, a part having a cylindrical bore which at one endterminates In a seating for the closure member, and which is occuitsclosed position on the seating, and a byass pase barrel pied by thecylindrical land when the closure member is

